Background <p>Lumbar disc surgery is one of the most commonly performed spinal procedures and is generally considered safe. However, rare complications such as major vascular injury can be life-threatening and are often difficult to recognize intraoperatively. These injuries most commonly involve the iliac vessels because of their close anatomical relationship to the L4–L5 disc space. Early diagnosis is challenging, and delayed recognition is associated with significant morbidity and mortality. With advances in endovascular techniques, minimally invasive management has emerged as an effective alternative to open surgical repair. Reporting such cases remains important to improve awareness, highlight diagnostic pitfalls, and illustrate evolving management strategies.</p> Case presentation <p>A 32-year-old previously healthy female presented with right lower limb radiculopathy due to an L4–L5 disc prolapse. She underwent elective minimally invasive tubular L4–L5 discectomy. During surgery, unexpected bleeding from the disc space was noted but appeared controlled with local measures. In the immediate postoperative period, the patient developed hypotension, tachycardia, and altered consciousness, along with a significant drop in hemoglobin and rising serum lactate levels. Computed tomography angiography demonstrated a large left retroperitoneal hematoma with active contrast extravasation and non-opacification of the left common iliac artery, consistent with major arterial injury. Emergency angiography confirmed the diagnosis, and endovascular covered stent placement was performed, achieving immediate hemostasis. The postoperative course was complicated by hemorrhagic shock, coagulopathy, and transient neurological deficits related to mass effect from the retroperitoneal hematoma. With intensive care support, blood product transfusion, and multidisciplinary management, the patient gradually stabilized and recovered. She was discharged in stable condition with improving neurological function and ongoing outpatient follow-up.</p> Conclusions <p>Major vascular injury during lumbar disc surgery is rare but potentially fatal and may not be immediately evident during the procedure. Sudden postoperative hemodynamic instability should raise suspicion for vascular injury and prompt urgent imaging. Early computed tomography angiography and rapid endovascular intervention can be life-saving and may avoid the morbidity associated with open surgical repair. This case emphasizes the importance of early recognition, multidisciplinary collaboration, and the growing role of endovascular techniques in managing vascular complications of lumbar disc surgery.</p>